Fabricate, characterize, package, and distribute 25,000 sheets and 1,500 tubes of each of two primary reference materials; silica-free polydimethylsiloxane and fluorinated ethylene propylene. The program also includes a one-year feasibility study for fabricating small spherical beads of PDMS. Sheets of both materials will have a thickness of 0.0254 cm. PDMS sheets shall be 2.54 cm. x 7.62 cm. FEP sheets will no greater than 15 cm. by 15 cm. Tubes will have an outside diameter of 5 mm., an inside diameter of 4 mm., and a wall thickness no greater than 0.5 mm. Each characterized sample will be wrapped in thin sheets of the same material and packaged in heat-sealable aluminum foil.